1. Field of the Invention
This invention relates to a reciprocating mechanism for a forging machine, more particularly to a reciprocating mechanism that transfers a driving force without vibrating a swing mechanism of the forging machine.
2. Description of the Related Art
Referring to FIG. 1, a conventional forging machine 1 is shown to comprise a machine frame 11, a plurality of female dies 12 mounted on the machine frame 11, a support member 13 mounted on the machine frame 11 above the female dies, and a swing mechanism 15 connected movably to the support member 13. The swing mechanism 15 includes a swing plate 14 and a plurality of workpiece holding members 151 connected operatively to the swing plate 14. The swing plate 14 is connected to a conventional reciprocating mechanism in order to reciprocate in a left-and-right direction in FIG. 1 via a horizontal linkage mechanism 18. During the reciprocal movement of the swing plate 14, the workpiece holding members 151 hold and transfer in sequence blanks to the female dies for carrying out subsequent punching processes.
Referring to FIG. 2, the conventional reciprocating mechanism includes an inverted Y-shaped rocker arm 17 having an upper end connected pivotally to the horizontal linkage mechanism 18, and two separate lower ends 172 that engage alternately a cam member 16 when the cam member 16 is driven to rotate. The rocker arm 17 swings to reciprocate the swing plate 14 via the horizontal linkage mechanism 18.
The disadvantage of the conventional reciprocating mechanism resides in that, because the torque applied to the horizontal linkage mechanism 18 is opposed to the inertia of the horizontal linkage mechanism 18 and the swing plate 16 at two dead points of each stroke of the rocker arm 17, the upper end 171 of the rocker arm 17 is liable to flex and vibrate at the dead ends. The vibrations of the rocker arm 17 will transfer to the swing plate 14 via the horizontal linkage mechanism 18, thereby resulting in shaking or wobbling of the swing plate 14. The shaking or wobbling of the swing plate 14 adversely affects the subsequent punching processes.